1. Field of the Invention
The present invention relates to an apparatus and a method for controlling a high power amplifier in a communication system. More particularly, the present invention relates to an apparatus and a method for controlling a high power amplifier in order to optimize the efficiency of the high power amplifier according to the intensity of an input signal.
2. Description of the Related Art
In communication systems of the related art, a high power amplifier outputs a Radio Frequency (RF) output signal with a predefined power level.
FIG. 1 is a block diagram illustrating a structure of a high power amplifier according to the related art.
Referring to FIG. 1, the high power amplifier includes a drive amplifier 101 and a main amplifier 103. Each of the drive amplifier 101 and the main amplifier 103 receives a fixed drain bias and gate bias applied thereto, amplifies an RF input signal, and outputs an RF output signal. These high power amplifiers output RF output signals according to a fixed drain bias regardless of the communication environment. For example, the high power amplifiers output RF output signals according to a fixed drain bias regardless of the time of day. However, communication systems are typically used more during the day than the night.
Meanwhile, as communication systems become more complicated, have a wider variety of functions, and require higher data transmission/reception speeds, the efficiency of the communication systems has emerged as an important issue.
However, the high power amplifier, which operates based on a fixed drain bias and outputs the RF output signal with constant power intensity regardless of the communication environment, is one of the main factors degrading the efficiency of the communication systems. Such degradation in the efficiency of the communication systems may increase the operation cost of the communication systems. Also, in order to overcome the low thermal efficiency of the high power amplifier, the high power amplifier may be equipped with a large heat sink or employ an enhanced cooling method, which may enlarge the entire size of the high power amplifier. Therefore, there has been a desire for a solution capable of optimizing the efficiency of the high power amplifier in order to minimize the heat radiation and size.